Method of surf generation

ABSTRACT

A tapered enclosure for a body of water has a wave generator positioned in a relatively narrow and deeper end. In one form, the wave generator is a buoyant plunger mounted for vertical reciprocation within a chamber having a shorewardly facing opening. Through a cyclic control system, the plunger is driven in phase with the forces of gravity and buoyancy acting thereon, starting from a rest position through strokes of increasing amplitude until a desired steady state is attained to sequentially produce waves of a desired energy. Provision is made for varying the mass of the plunger and varying the input from a prime mover as a means of adjusting wave energy and frequency.

United States Patent [191 Richard et al.

[ 4] METHOD OF SURF GENERATION [22] Filed: Mar. 27, 1972 [21] Appl. No.:238,245

Related US. Application Data [62] Division of Ser. No. 56,314, July 20,1970.

[52] US. Cl. 307/118, 73/148 [51] Int. Cl. H0111 35/24 [58] Field 01'Search. 73/170 A,,290, 308, 314, 319,

[56] References Cited UNITED STATES PATENTS 3,287,967 ll/l966 Laurent73/148 MOME'NMZV lam/11 44 I K 55 [4 1 Feb. 19, 1974 PrimaryExaminer-Herman .l. Hohauser Attorney, Agent, or Firm-Frederick E.Mueller [57] ABSTRACT A tapered enclosure for a body of water has a wavegenerator positioned in a relatively narrow and deeper end. In one form,the wave generator is a buoyant plunger mounted for verticalreciprocation within a chamber having a shorewardly facing opening.Through a cyclic control system, the plunger is driven in phase with theforces of gravity and buoyancy acting thereon, starting from a restposition through strokes of increasing amplitude until a desired steadystate is attained to sequentially produce waves of a desired energy.Provision is made for varying the mass of the plunger and varying theinput from a'prime mover as a means of adjusting wave energy andfrequency.

4 Claims, 8 Drawing Figures mime sw/zzw PATENTEDFEB 19 I914v 3393534 sum1 or 3 I I Fa in PATENTEUFEB 19 1974 SHEET 3 OF 3 umzev i1 METHOD OFSURF GENERATION This is a division, of application Ser. No. 56,3l4,filed July 20, 1970.

BACKGROUND OF THE INVENTION This invention relates to the artificialproduction of ocean-like surf of recreational utility.

It is known in the art to generate waves for amusement purposes,cinematic effects, demonstrations of wave interference phenomena, modelstudies or the like. However, so far as the prior state of the art isconcerned, it hasnot heretofore been possible to produce waves of oceanmagnitude and energy, specifically adapted for surf riding and the like,on an efficient and economical basis. Typically, wave generation hasbeen performed with devices which require great amounts of power whenattempted to be used to produce waves of any real recreational utility,i.e., of suitable size, shape and energy. These devices employ strictlyscheduled and fixed processes of mechanical movement which inhibitefficient wave generation. As a result, excessive prime mover capacityand unduly massive'structures have been required in order to withstandthe forces involved, when applied to full scale wave generation. Inaddition, previously available systems are not adapted to utilize theirwave energy by channeling it to produce waves of a desired energy thatbreak along predetermined trajectories.

SUMMARY OF THE INVENTION The wave generator comprises a massive buoyantergy conserving chamber. A control system maintains the driving force onthe plunger in phase with the natural frequency of the plunger,enablingdisplacement of large volumes of water with minimal energy and powerrequirements. The amount of displaced water, the rate of displacementand the depth of water determine the height, length and period of the'wave propagated by the wave plunger. The wave characteristics may bevaried by adjustment of the plunger driving force or the plunger mass.The control system includes a pilot means that automatically compensatesfor the gradue ally increasing amplitude of plunger stroke duringstarting, switching the input of the power means between plunger raisingand plungerlowering modes in a way to reinforce the natural oscillatorymotion of the plunger, to gradually increase the amplitude of theplunger stroke to a desired steady state.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a surfgenerating system embodying theinvention;

FIG. 2 is a view similar to FIG. 1, on a smaller scale,

- showing trajectories of wave break for waves of a given FIG. 7 is atopplan view of the wave generator apparatus;

DESCRIPTION OF THE PREFERRED EMBODIMENTS As will be apparent, theinvention may be employed in natural or artificial bodies of water. Forexample, referring to FIG. I, the system may comprise an enclosure,designated generally by the numeral 10, of a predetermined planformhaving fluid communication with a larger natural or man-made body ofwater 11. The enclosure I0 is generally bounded by the structure of awave generator chamber I2-opening towards a shoreline 13 and, onopposite sides, by walls 14 and 15 which also comprise boundaries ofspits of land 16 and 17, respectively. Water from the larger body ofwater 11 is admitted into the enclosure through an inlet passage 18,adjacent the wave generator chamber 12, and passes out of the enclosure10 at an outlet 19, between the shoreward end of the wall and theshoreline 13. The chamber 12 contains a wave generator apparatus 20,oriented to generate successive waves in a shoreward direction.Enclosure 10 is formed with a floor 21,

generallysloping upwardly towards the shoreline I3,

and so oriented with respect to the generator 20 as to producesuccessive waves spanning the width of the enclosure 10, with each wavebreaking laterally from right to left as viewed in FIG. I.

The specific example of FIG. 1 is adapted for an installationencompassing approximately 60,000 square feet of water surface in a.coveof approximately 300 feet in length, from the generator 20 to a parallelline tangent to the shoreline 13. Since the topography of the floor 21is essential in controlling the wave break it should be constructed of amaterial which is not subject to erosion as a result of the wave action.Accordingly, the floor 21 is preferably made of concrete or heavy rock,in the deeper portions at least, while sand may be distributed over theshallower portions and beyond the shoreline 13 onto a surrounding beach22. By the same token, in order to give permanence to the desiredplanform'of the enclosure 10, the side walls 14 and 15 are made ofreinforced concrete, pilings, or the like.

The chamber 12 containing the wave generating apparatus is of a heavyconstruction to provide a stable support for the apparatus. Thus, as isindicated in FIG. 5, the generally U-shaped chamber is formed with aheavy footing 25 and surrounding wall 26, which may be of reinforcedconcrete, .the entire chamber rising substantially above the undisturbedwater level at the deeper end of the enclosure 10. As is shown in FIG.6, the rear wall of the chamber may be formed with an elevated portion27 on top of which a rigid framework 28, composed of appropriate box,channel or I beam members, may be anchored to project forwardly as asuperstructure for connection to the upper end of the wave generatingapparatus and to support various components thereof. The framework 28substantially spans the length of the chamber 12 and, adjacent oppositeends, is rigidly connected to a pair of heavy columns 29, the lower endsof which are securely anchored within the footing 25.

As is best shown in FIGS. Sand 6, the columns 29 serve as guide meansfor constraining a massive plunger 30 for reciprocation in a verticalplane. The plunger may be made of a variety of materials, such as wood,concrete, or metal, and in a variety of sizes, proportional to themagnitude of waves desired to be produced. For example, in a layout suchas that of FIG. 1, the chamber 12 may be approximately 40 feet inlength, i.e., between the side walls, with a depth of ap proximatelyfeet in order to accommodate, with clearance, a plunger on the order of38 feet long, '12 feet wide and 8 feet in depth or height. In any event,what is desired is a plunger capable of sufficient water displacement togenerate waves of the desired height, that is buoyant, and, also, is ofgreat mass, in order to utilize the forces of buoyancy and gravity inreciprocating the great mass of the plunger, with sufficient verticalamplitude of stroke to generate desired wave heights. In the presentexample, the mass and buoyancy of the plunger 30 are variable, asdesired, and the control means includes a means for selectively limitingthe input force whereby the apparatus is capable of generating waves ofdifferent energy and magnitude through a wide range.

More specifically, the illustrative plunger 30 comprises an essentiallywaterproof metal tank made ofappropriately reinforced sheet steel that,at opposite ends, is internally rigidly provided with a vertical pair ofguide sleeves 31 that slideably receive the pair 'of guide posts 29. Thetank-like plunger 30 is provided with a filler opening means, not shown,by means of which a ballast material 32, for example a portion of theambient water, may be introduced into the plunger in order to achieve apredetermined plunger mass. [f a liquid such as water is employed as theballast 32, slosh or baffle plates, or the like, may be providedinternally of the tank-like structure in order to inhibit undesiredrandom movement of the ballast material out of phase with the'motion ofthe plunger.

The superstructure framework 28 mounts a spaced pair of pneumaticcylinders 33 adjacent the opposite ends of the plunger 30. As is shownin FIGS. 5 and 6, the cylinders 33 are vertically disposed, each havinga downwardly projecting piston rod 34 extending inwardly into theplunger 30 for driving connection, at a lower end, to one ofa pair ofcross beams 35 rigidly affixed between opposite side walls of thetank-like plunger 30. it will be appreciated that the pneumaticcylinders 33 are illustrated. schematically only but, in actuality, areof a sufficient length to provide a sufficient amplitude of stroke toaccomplish the desired amplitude of reciprocation of the plunger 30. Atthe same time, the plunger 30, when adjusted for the desired mass, seeksits own equilibrium level relative to the normal still water level ofthe enclosure 10. Accordingly, the piston rods 34 preferably eachcomprise a sleeved pair of members capable of being interlocked by alocking means 36 to achieve the proper degree of extension of the pistonrods 34 for each different equilibrium level of the plunger. Thisadjustment means may take the form, for example, of slots or holes 37formed in one portion of the piston rod assembly, as indicated at 37,spaced longitudinally thereof, and adapted to receive the locking pinmeans.

As is schematically shownin FIG. 4, the cylinders 33 are connected to anappropriate source of compressed air by means of a conduit 40, having anadjustable pressure regulator 41 interposed therein, a four-way solenoidvalve 42, and appropriate manifolds 43 and 44. The cylinders 33 are,preferably, of the double acting type and, accordingly, the manifold 44is connected between each cylinder 33 and the valve 42 in a manner tointroduce compressed air to the lower end of each cylinder 33 beneaththe piston. Conversely, the manifold 43 is interconnected between thevalve 42 and the upper end of each cylinder 33 for cyclicallyintroducing compressed air to the upper end of the cylindcr above thepiston. The valve 42 is also provided with an outlet 45 for alternatelyventing to the atmosphere air being discharged from either the upper orlower ends of the cylinders 33. ln addition, thevalve 42 has a neutralposition in which both of the manifolds 43 and 44 are vented toatmosphere through the outlet 45.

The solenoid valve 42 has a pair of terminals 46 and 47 connected inelectrical parallel to opposite contacts 48 and 49 respectively of asingle-pole double throw switch 50. A power supply 51 is connected tothe switch via a main power switch 52 and to a common terminal 53 of thesolenoid valve 42. The arrangement is such that when the solenoidterminal 46 is energized compressed air is admitted to the lowermanifold 44, while the upper manifold 43 is simultaneously incommunication with the atmospheric outlet 45. Conversely, when thesolenoid terminal 47 is energized compressed air is delivered throughthe manifold 43 .to the upper end of the cylinders 33, while the lowermanifold 44 is then vented to atmosphere via the outlet 45. When thepower switch 52 is open, the solenoid valve 42 returns to a neutralposition in which both manifolds 43 and44 are vented to atmospherethrough the outlet 45.

The switch 50' comprises a portion of a pilot means adapted to translatereversals of the direction of oscilla tion of the plunger 30 intocorresponding actuation of the solenoid valve 42 for delivering power inphase with the upward or downward movement of the plunger. Since theplunger 30 has neither upward or downward sense when it is at rest, amomentary manual switch 55 is utilized to initiate the plungermotion'to, in turn, actuate the pilot means which,thereafter,automatically accomplishes actuation of the valve 42 todeliver power in phase with the plunger motion. Accordingly, a momentarymanual switch 55 is connected between the solenoid valve terminal 46 andthe power supply 51. As a result, closing of the switch 55 opens thevalve 42 in a manner to admit compressed air to the lower manifold 44 toinitiate upward movement of the pistons in the train of cylinders 33,concurrently venting the upper end of the cylinders to atmosphere. Thecylinders 33 force the plunger 30 upwardly above its equilibriumposition only a few inches on this initial input of power,simultaneously actuating the pilot means.

The switch 50 includes a switch arm 57 that is pivotally mounted, as at58, to make and break contact with the opposed switch contacts 48 and49. This switch arm is a longitudinal extension of a switch actuatingarm 59 having a lost-motion connection with a vertically elongated rod60 that is affixed to and carried by the plunger 30. Thus, as can beseen from FIG. 5a, the outer end of the switch actuating arm 59telescopically slidably contains a rod 61 with a bifurcated outer end 62mounting a roller 63 in frictional rolling engagement with a flat sideor track of the member 60. A spring 64 within the actuating arm 59effects biasing of the roller 63 into contact with the member 60throughout the arcuate range of movement of the switch actuating arm 69.

As will now be apparent, initial upward movement of the plunger 30effects corresponding upward movement of the member 60 with consequentcounterclockwise pivoting of the switch arm 59 to close contact 48.Then, when the gravitational force of the plunger 30 overcomes thelifting forces on the plunger, to reverse the plunger direction, theswitch actuating arm 59 pivots clockwise as the gravitational force ofthe plunger effects lowering of the elongate member 60. Accordingly, theswitch arm 57 now makes contact with the other switch terminal 49,energizing the solenoid valve 42 to admit compressed air to the top ofthe pistons in the cylinders 33, while air in the lower ends of thecylinders is bled to atmosphere through the manifolds 44 and outlet 45.Compressed air now augments the mass of the plunger to move the plunger30 downwardly below its equilibrium position until overcome by theincreasing buoyant force on the plunger 30. Consequent reversal andrising of the plunger 30 effects another reversal of the switch 50,initiating a new cycle of reciprocation of the plunger, again or withthe force of buoyancy now being augmented by the force of the compressedair.

It will be seen that this cycle continues, with each stroke of theplunger 30 being reinforced so that the amplitude of the plunger strokegradually increases until a steady state condition is attained, themagnitude of the amplitude being a function of the mass of the plungerand the preadjusted compressed air input.

In order to deactivate this system, the power supply 51 is merely shutdown by opening of the switch 50. As a result, the valve 42 returns tothe neutral position. As both the upper and lower manifolds 43 and 44are open to atmosphere, the plunger is then free to oscillate withnatural declining frequency.

Steady state amplitude and frequency of the plunger 30 are adjustable byvariation of the air pressure by adjustment of the regulator 41, and byvarying the plunger mass, as by varying the amount of the ballast 32. Byso controlling the motion of the plunger, water waves of variouscharacteristics of height, frequency and wave length are generated.

As will now be apparent, the drive system just described may be modifiedwhereby compressed air is delivered to single acting cylinders in phasewith only one or the other of the forces of buoyancy and gravity act ingon the plunger 30. While not as efficient, such modificationnevertheless attains the objective of phased reinforcing the naturaloscillatory motion of the plunger 30, to displace large volumes of waterwith minimal energy and power requirements. It will also be apparentthat other types of drive systems may be employed for delivering energyin phased relation with either or both of the forces of buoyancy andgravity acting on the plunger. For example, a cable system reeved on asuitable array of pulleys and drums employing slip clutches may beconnected to either the top or bottom or both of the plunger 30, theslip clutches being adjusted for release at predetermined degreesoffrictional engagement. H

FIG. 1 illustrates a presently preferred overall planform and underwatertopography of the enclosure 10,

that is adapted to make optimum utilization of the waves cyclicallygenerated by th'egenerator 20. Within the given area of the enclosure10, the combination of planform and underwater topography are adapted toprovide optimum wave break forms; a maximum length of surf board run;generation and regeneration of breaking waves out of a single cycle ofactuation of the generator 20; areas in which waves do not break to beutilized as pathways as surfboards returning to the initial wavebuild-up area or as calm swimming and diving areas; and a shallow waterregion where waves are patterned to break in an optimum manner for bellyboarding, surf rafting and body surfing.

For the foregoing purposes, it will be observed that one side wall 14comprises a continuation of one side wall of the chamber 12, projectingshorewardly in a direction normal to the plane of the opening of thechamber 12. The other side wall 15 diverges shorewardly away from theopposed side wall 14 to the shoreline. The shoreline 13 curves away fromthe longer wall 15, beyond the projection of the relatively short wall14, and thence curves towards the short wall 13 to merge thereinto at alocation approximately opposite to the approximate mid point of thelength of the wall 15.

The topography of the floor 21 of the enclosure 10 is shown by contourlines 90, each being marked with its'depth in feet below the meanorstill waver level of the water contained in the enclosure. lt will beobserved that the relatively deep water contour lines, immediatelyadjacent the opening of the chamber 12, range spanwise of the walls 14and 15 in a direction generally paralleling the plunger of the generatorapparatus 20, but gradually define more acute angles with the long wall15 with decrease in depth along that wall. It will be observed, also,that certain contour lines a do not span the entire width of theenclosure 10 but, instead, define loops indicating a second deep waterportion of the enclosure 10, elongated generally in a directionangularly related to the longitudinal axis of the plunger of thegenerator apparatus 20 and tending towards parallelism withthe long wall15 The dashed line 91 of FIG. 1 illustrates the trajectory of the pathof the leading edge break of a primary wave generated by the apparatus20. Thus, the wave initially breaks immediately in front of thegenerator apparatus 20 at the end 91a of the line, characterized as afast and steep breaking wave section. Immediately thereafter,

due to the divergence of the walls 14 and 15 and the graduallydecreasing shallowness of the water, the wave height will graduallydiminish as the wave progresses shoreward. As a consequence, the wavebreak decreases gradually along the line 91, requiring numerous turningmanueuvers by the surfer to maintain an optimum position in the wave ifhe is to successfully complete a run for the full length of the line 91.

The second deep water portion of the floor 21, as represented by thecontour lines'90a, defines a regenerating cavity utilizing the energy ofa previously broken primary wave to reform the wave before it has lostall of its energy of turbulence. This regenerating cavity approximatelycorresponds in its longitudinal aspect to the initial portion of thepath of the primary wave break, as indicated by the line 91, and effectsreforming of the wave energy into a new secondary wave in the cove-likeshallow water portion indicated at 92, as illustrated by the wave breaktrajectory along lines 93 and 94 in FIGS. 2 and 3.

Referring to FIG. 1, it will be seen by comparison of the wave breaktrajectory line 91 and the adjacent wall 15 that the topography of theenclosure bottom is such that waves do not break withinthis strip ofwater, generally indicated at 95. Similarly, waves do not break withinthe regenerating cavity included within the second deep water contourlines 90a, so that these two areas are useable as pathways for surfboards returning to the initial wave build-up, or as relatively calmswimming and diving areas.

FIG. 2 illustrates the manner in which the topography of the enclosurebottom 21 accomoodates different wave heights of a given period inproducing the wave break trajectories shown, both for the primary andsecondary trajectories 96 and 93, respectively. As is shown bycomparison of the five foot, four foot and three foot primarytrajectories 96, the larger waves break in deeper water and yield afaster ride:

FIG. 3 illustrates different wave break primary and secondarytrajectories 97 and 94, respectively, resulting from different wavegenerator frequencies. When the plunger is more massive, the period T ofthe wave increases as the plunger moves more slowly. For a given waveheight, the wave of the longer period, e.g., 7 seconds, will yield afaster ride with a more critical and powerful wave section threateningthe rider as he tries to escape in front of the break. The same resultfollows with the secondary wave break trajectories compared in theshallower cove area 92.

A protective barrier 99 may be provided in the opening of the chamber 12to prevent a user being drawn into contact with the generator 20. Thisbarrier may take the form of heavy wire-mesh fencing, as shown, orlaterlly spaced vertically and/or horizontally disposed rods or otherrelatively open rigid means that will not unduly disturb the formationof waves emitted from the chamber 12. As will be apparent, if the wavegeneration is accomplished by a row of relatively small, synchronizedplungers in individual chambers, rather than by a single large, greatlyelongated plunger of the given example, each chamber may be providedwith its own safety barrier.

While certain presently preferred embodiments of the invention have beendisclosed, it will be apparent that various modifications in the design,arrangement of ports and instrumentalities of the invention areobviously possible.

We claim:

1. A control circuit for cyclically interconnecting source of power to avertically reciprocable water wave plunger throughout a range ofamplitudes of plunger reciprocation comprising:

means interconnecting the power means to the plunger for driving theplunger in one, at least, direction of reciprocation;

switch means, in said first mentioned means, to connect and disconnectthe source of the power and the plunger:

and a pilot means, operatively associated with the plunger, adapted totranslate at least one of the reversals of direction of reciprocation ofthe plunger into actuation of said switch means for operative connectionof the power means and the plunger for driving the plunger in said one,at least, direction of reciprocation. t

2. A control circuit as in claim 1 in which said pilot means includes avertically elongate member carried by the plunger for verticalreciprocation therewith and a lost motion means adapted to permitvertical movement of said member, within variable limits, withoutactuation of said pilot means.

3. A control system as in claim 1 in which said pilot means includes anactuating lever engaged with said member through said lost motion means.

4. A control circuit as in claim 2 in which said pilot means includesbiasing means interposed between said lever and said member formaintaining contact between said lost motion means and said member.

' UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTION Pzent No.3,793,534 j I Dated February 19, 1974 g George E. Richard, Eugene D.v,Riehard It is certified jthat errora ppeaxs' in theabove-identified'patent and that said LetterQ-Patent are herebycorrected as shown. below:

In 'thei-ti tfle', ch'nge "Method 6f Surf GeheTation" I to -'-Cofi rolAppa r ati l s fer- Generation- Signed and sealed this 19th day ofNovember 1974.

(SEAL) I A =e M GIBSON JR". I. 0.. MARSI IALL DANN Az gzting OfficerCommissloner of Patents.

FORM PO-1050 (10- USCOMH-DC 60376-P69 U.5 GOVERNMENT PRINT NG O a 69, Q30 I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Pm: No. 3,793,534 E j Dated February 19, 19-74 znvemoflw George B. Richard, EugeneD. ,Rithard It is certified 'tlfiat error-appeaz 's the above-identifiedpatent and that said Letteriatent are hezeby corrected as shown below;

In 'thej'ti t le', 'ch'ng'e "'Method 6f Surf G ehefati on" I to -'-Cofi1rol A ppa r-ti lsf 50 1 Generationx I v -'1 Claijh llin one :Ch ei nige'thg r rumer'al" "1" to the num'e fl --2'-- ;Q 1- -1 I I E I"n=.Ci'a'iim;;-4,' .icl'lgln g qaf "2 "to the numeral si n d and sealed this 19thday of November 1974- (SEAL) l A e E I 0.. MARSHALL DANN I JR'. MCCOYGIBSON Commissioner of Patents Attesting Office? USCOMM-DC 60376-P69U.S. GOVERNMENT PRINTING OFFICE:

FORM Po-wso (10-

1. A control circuit for cyclically interconnecting a source of power toa vertically reciprocable wAter wave plunger throughout a range ofamplitudes of plunger reciprocation comprising: means interconnectingthe power means to the plunger for driving the plunger in one, at least,direction of reciprocation; switch means, in said first mentioned means,to connect and disconnect the source of the power and the plunger: and apilot means, operatively associated with the plunger, adapted totranslate at least one of the reversals of direction of reciprocation ofthe plunger into actuation of said switch means for operative connectionof the power means and the plunger for driving the plunger in said one,at least, direction of reciprocation.
 2. A control circuit as in claim 1in which said pilot means includes a vertically elongate member carriedby the plunger for vertical reciprocation therewith and a lost motionmeans adapted to permit vertical movement of said member, withinvariable limits, without actuation of said pilot means.
 3. A controlsystem as in claim 1 in which said pilot means includes an actuatinglever engaged with said member through said lost motion means.
 4. Acontrol circuit as in claim 2 in which said pilot means includes biasingmeans interposed between said lever and said member for maintainingcontact between said lost motion means and said member.